*jTum?l,Feri'^86rT PROGRESS OF MICROSCOPICAL SCIENCE. 125 
The ripe forms are distinguislied from the unripe ones by having 
a cuticula developed, which makes them much more resistant. 
" Macroconidia " is the term which Professor Hallier applies to 
dilatations such as occur in mucor racemosus. He believes that they 
are unripe forms of fructification, and are capable by a ripening 
process of becoming Tilletia caries spores ; but in place of ripening 
they may, unlike the ripe spores, germinate at once. If the soil on 
which this germination takes place be sour and poor in nitrogen, 
penicillous forms result, i. e. the unripe representative of the clado- 
sporiiun. If, on the other hand, the soil be rich in nitrogen, mucor 
forms appear, i. e. the unripe representative of the schizosporangium. 
A schizosporangium is precisely the same as a mucor sporangium, 
save that it has a cuticula developed on its exterior, and that the 
contained spores are each provided with a sheath. 
The mode of germination in the two forms is quite distinct. Each 
spore on a schizosporangium. on germinating gives origin to a fila- 
ment, which pierces both the sheath peculiar to the spore and the 
wall of the containing capsule, without rupture having taken place. 
In the mucor sporangium, on the contrary, rupture or disappearance 
of the capsule always takes place before germination, as it, being 
destitute of a cuticula, is not strong enough to resist the pressure of 
the swelling spores. The only form of the series associated with 
cholera which is peculiar to the disease is the schizosporangium or 
the cholera cyst ; but they may probably on investigation be found to 
occur on the rice plant in India. The schizosporangia of the cholera 
series are in this climate peculiar to the disease only. They can only 
be developed on a nitrogenous basis, and under a high temperature. 
Cholera originates under the same conditions in which true cysts can 
be produced. This may possibly cause the difference between Asiatic 
and European cholera — the first being due to the micrococci of the 
schizosporangia; and the second to the micrococci of their unripe 
representatives, mucor sporangia, as well as to the indigenous ripe 
form, tilletia spores. 
Professor Hallier does not state positively that cholera is due to 
the fungus, and he does not believe that any infectious disease can be 
caused by spores per se. It is only micrococci that are efficient 
agents in producing disease. This may account for the fact that 
tilletia spores can be, and constantly are, swallowod in large quantities 
without producing any bad effects. They are not retained long 
enough in the intestinal canal to produce micrococcus, and therefore 
pass through quite passively. 
The question of " micrococcus " being thus introduced, Professor 
Hallier stated his views on the subject. He defines micrococcus as 
" particles of plasma without any cell-wall." When these particles 
acquire such a wall they become either " cryptococcus " or " arthro- 
coccus," according to the nature of the medium in which they are 
contained. Micrococcus, on being introduced into a fluid capable of 
alcoholic fermentation, becomes cryptococcus, corresponding with the 
bodies which are generally included under the vague term "yeast 
cells." If, on the other hand, micrococcus be introduced into a fluid 
